With the increase in integration density of semiconductor devices, various design and fabrication methods for increasing the area of a storage contact have been proposed.
An ISO 14443 type A smart card is configured to receive signals in an amplitude shift-keying (ASK) communication mode having a modulation index of 100%. Clock signals used in the smart card may be generated from carrier signals of radio-frequency (RF) signals received from a card reader. However, the RF signals received by the smart card may have a carrier frequency of about 13.56 MHz, and pause periods may be present between transmission bursts of the carrier signals. The carrier signal is absent during the pause period, making clock signal generation during the pause periods problematic. As a result, timing margin and frame delay time (FDT) margin required to restore signals may be reduced, which may cause communication failure.